Th invention relates generally to aircraft navigation apparatus used during an approach, and more particularly to apparatus combining an inertial reference system (IRS) using air data inputs with the Global Positioning System (GPS) and a radar altimeter. This apparatus can be used on a worldwide basis to replace non-precision approach procedures with 3-dimensional approach procedures, without the use of any ground-based augmentation systems.
It is generally recognized that it will be many years before satellite navigation augmentation systems, such as the wide-area augmentation system (WAAS) and equivalent systems, will provide such a capability. As stated in Aviation Week magazine, 8/18/97, pp 23, 26, "nonprecision approaches are associated with 60% of the commercial airline crashes worldwide that are attributed to controlled flight into terrain (CFIT)" and "CFIT is the leading cause of fatal accidents in commercial aviation." "[I]t will be at least 10-15 years before fully autonomous, airborne navigation systems with 3-D capabilities are available to replace them".
The technology required for fully autonomous airborne navigation systems with 3-D capabilities already exists today in the proven 3D AIME.TM. system of the present invention. Unlike WAAS, the 3D AIME.TM. system will be available on a worldwide basis autonomously on the aircraft, without using any ground based navigation aids.